Isolation and structure characterization of a polysaccharide from Crataegus pinnatifida and its bioactivity on gut microbiota

A glucose rich heteroglycan named HAW1-2 was isolated and purified from fruit of Crataegus pinnatifida by hot-water extraction, ethanol precipitation, DEAE-cellulose anion exchange and gel permeation chromatography. HAW1-2 was proved as a homogenous polysaccharide with amolecular weight (Mw) of 8.94 kDa. Monosaccharide composition results indicated that HAW1-2 was composed of arabinose, galactose and glucose. Methylation analysis and NMR spectrum showed that HAW1-2 contained -> 4)-beta-D-Glcp-(1 ->,-> 4)-beta-D-Galp-(1 ->, alpha-L-Araf(1 ->,-> 5)-alpha-L-Araf-(1 ->, beta-D-Glcp-(1 -> and -> 4,6)-beta-D-Glcp-(1 ->. Bioactivity test showed that HAW1-2 could significantly promote the growth of Bacteroides thetaiotamicron (BT), Bacteroides ovatus (BO) and Bifidobacterium longum (BL), which showed competition with the Bacteroides spp. under co-culture. Interestingly, Bacteroides spp. generated more acetic acids and propionic acids while BL only generated acetic acids. These results imply that polysaccharide HAW1-2 may be useful for human by modulating intestinal bacteria and producing short chain fatty acids. (C) 2020 Elsevier B.V. All rights reserved.